What makes this particular ruin at Templepatrick quietly compelling is the depth of time compressed into a single spot: the collapsed slate roof and crumbling coursed rubble limestone walls of an early nineteenth-century corn mill occupy very nearly the same ground as a watermill that was already considered worth mapping in 1659.

The 1659 Down Survey, a massive Cromwellian-era land mapping project, recorded a watermill in the townland of Templepatrick on its map of Rathconrath Barony. The accompanying terrier, a written description of landholdings prepared alongside the survey, noted that on the lands of Templepatrick there was 'a Mill and some Cabbins'. The Down Survey depiction was specific enough to show a waterwheel on the gable of the building. No surface trace of that medieval mill survives today, but when the Ordnance Survey produced its six-inch map in 1837, the corn mill it recorded sits in roughly the same location, suggesting continuity of use on the site across several centuries. The present structure dates to around 1820 and was built in coursed rubble limestone with brick dressings around the openings, including a segmental-headed arch on the east elevation through which the waterwheel once turned. A small corn kiln, a low stone structure used to dry grain before milling, stands in ruins to the south of the main building. By 1979, one tin wheel remained in place, though no internal machinery was visible at that point. The roof has since collapsed entirely, and cast-iron remnants inside are all that survive of the working mill.

The building sits set back from a minor road to the west, overgrown and out of use. The waterwheel arch on the east elevation is said to retain its brick voussoirs, the wedge-shaped stones that form the curve of an arch, and is worth looking for as one of the more intact architectural details remaining on the structure.